VENT GAS ABSORPTION SYSTEM AND METHOD FOR RECOVERY VOCs

Abstract

The present invention relates to a vent gas adsorption system and a method of recovering volatile organic compounds (VOCs), more particularly to a vent gas adsorption system devised to effectively adsorb VOCs included in the vent gas and reduce VOC content of the vent gas, and a method of recovering VOCs.

1 . A vent gas adsorption system comprising:
 an adsorption tower which adsorbs volatile organic compound (VOC) components contained in vent gas by circulating adsorption solvent therein, and discharges the removed gas with the VOC components to the outside;   a desorption tower which separates the VOC components from the adsorption solvent and recovers the VOC components by circulating a carrier gas therein; and   a storage tank that stores adsorption solvent,   wherein the removed gas is discharged via the storage tank to the outside.   
   
   
       2 . The vent gas adsorption system of  claim 1 , wherein the desorption tower is connected to the storage tank by a first recovery line, and
 wherein the removed gas flows through the first recovery line to the storage tank.   
   
   
       3 . The vent gas adsorption system of  claim 1 , further comprising a temperature control unit which controls the temperature of the adsorption solvent transferred to the adsorption tower and the desorption tower to be appropriate for the operating condition of each tower. 
   
   
       4 . The vent gas adsorption system of  claim 3 , said temperature control unit being a heat exchanger which cools and heats the adsorption solvent separated from the desorption tower and the adsorption solvent transferred from the adsorption tower to the desorption tower by heat exchange appropriate for the operating conditions of each tower. 
   
   
       5 . The vent gas adsorption system of  claim 4 , said heat exchanger further comprising a cooler and a heater on a feeding line and a transfer line connected to the adsorption tower and the desorption tower, so as to cool and heat the adsorption solvent transferred to the adsorption tower and the desorption tower. 
   
   
       6 . The vent gas adsorption system of  claim 1 , said adsorption tower being equipped with: a gas distributor at the bottom thereof, which distributes inert vent gas into the adsorption tower; a solvent distributor at the top thereof, which distributes VOC adsorption solvent to the bottom of the adsorption tower; a transfer line at the bottom thereof, which transfers the adsorption solvent having adsorbed the VOC components to the desorption tower; and several plates between the top and the bottom thereof, which are filled with packing materials that optimize contact of gaseous and liquid materials. 
   
   
       7 . The vent gas adsorption system of  claim 1 , said adsorption solvent being silicone oil another silicon-based compound. 
   
   
       8 . The vent gas adsorption system of  claim 6 , said desorption tower being equipped with: a distributor at the top thereof, which is connected to a transfer line and distributes the adsorption solvent into the desorption tower; a discharge line at the top thereof, which is connected to the reprocessing process; and several plates between the top and the bottom thereof, which are filled with packing materials that optimize contact of gaseous and liquid materials, and the carrier gas transferring the VOC components separated from the adsorption solvent to the reprocessing process fed from the bottom. 
   
   
       9 . The vent gas adsorption system of  claim 8 , wherein the feeding line at the side of the desorption tower is connected to the transfer line at the side of the desorption tower by a recycle line, and
 wherein at least a portion of the adsorption solvent from the desorption tower is re-introduced into the desorption tower through the recycle line.   
   
   
       10 . The vent gas adsorption system of  claim 10 , the temperature of said carrier gas being higher than the boiling point of the VOC components. 
   
   
       11 . The vent gas adsorption system of  claim 10 , said discharge line being equipped with a separator, which separates the adsorption solvent from the carrier gas and again feeds the separated adsorption solvent into the desorption tower through a recovery line. 
   
   
       12 . A method of recovering VOC components contained in vent gas using the system of  claim 1 . 
   
   
       13 . The method of recovering the VOC components of  claim 12  comprising the steps of:
 contacting the vent gas with adsorption solvent to adsorb the VOC components contained in the vent gas;   feeding hot carrier gas to the adsorption solvent having adsorbed the VOC components to separate them from the adsorption solvent;   transferring the VOC components with the carrier gas to a reprocessing process and recovering them; and   re-circulating the adsorption solvent with the separated VOC components to the VOC adsorption step.   
   
   
       14 . The method of recovering the VOC components of  claim 13  further comprising the step of heating the adsorption solvent prior to the VOC component separation step. 
   
   
       15 . The method of recovering the VOC components of  claim 13  further comprising the step of separating materials adsorbed to the carrier gas during the carrier gas transfer.